The present invention relates to an apparatus and method for controlling the positioning of optical fiber blocks and a Planar Lightwave Circuit, having an arrangement between an input and output optical fiber block for accommodating an optical fiber, and a Planar Lightwave Circuit, respectively.
In an optical fiber communication system which uses light, an optical fiber comprises a very fine strand or a cable of bundled-strands which are made of transparent resins such as glass, synthetic resins and the like. The optical fiber is used to transmit information signals and optical images etc. The thickness of the strand is about 3-60 xcexcm in glass. The optical fiber is of a step index type and a graded index type, etc.
The structure of the step index type includes the following: a core of a high refractive index, a clad of a low refractive index for molding the core, and a jacket for optical absorption which accommodates the core and the clad.
The graded index type has a lower refractive index from its center to its outer circular periphery. The light, in each mode for relating to the length of a fiber or a refractive index distribution, is transmitted by means of meandering or total reflecting in the core with a low-loss. A single mode fiber is one in which a fiber transmits only the lowest mode by way of making the core of the step index type small, and one in which has no mode dispersions and has wide transmission bands.
To branch a path of the above-mentioned optical fiber into plural paths, various devices, apparatuses and methods exist. Particularly, a positioning apparatus and its corresponding method which uses the Planar Lightwave Circuit are widely used. The Planar Lightwave Circuit comprises one or more input parts and a plurality of output parts, cores for forming light-waveguides and a clad for molding the cores. Accordingly, by fixing each core at the input parts and the output parts of the Planar Lightwave Circuit, one or more light-waveguides are branched into plural paths.
FIG. 1 is a schematic diagram of a conventional apparatus for positioning optical fiber 10 blocks and a Planar Lightwave Circuit, and FIGS. 2A and 2B are flowcharts according to FIG. 1.
As shown in FIG. 1, the reference numeral 10 is a laser source, the reference numeral 20 is an optical fiber, and the reference numeral 30 is an input optical fiber block. The optical fiber 20 comprises commonly a core (not shown) and a clad (not shown). One side of the optical fiber 20 is connected to the laser source 10, and another side is accommodated in the input optical fiber block 30. The laser source 10 generates light signals in order to generate an incident signal inside the optical fiber 20 that is the core and the clad. Accordingly, the optical fiber 20 makes the incident optical signals direct into the input optical fiber block 30.
The reference numeral 40 is a Planar Lightwave Circuit, the reference numeral 50 is a lens, the reference numeral 51 is an infrared camera, and the reference numeral 52 is a charge coupled device (CCD) camera. The Planar Lightwave Circuit 40 comprises one or more input parts 41a and plural output parts 41b at both of its ends so as to form waveguides for branching one or more inputs of optical signals into plural paths. One side of the Planar Lightwave Circuit 40 is positioned with the input optical fiber block 30. Here, the optical fiber 20 accommodated in the input optical fiber block 30, and the input parts of the cores of the Planar Lightwave Circuit 40, are positioned in accord with each other.
The CCD camera 52 receives image signals regarding to positioning the Planar Lightwave Circuit 40 and the input optical fiber block 30. The lens 50 and the infrared camera 51 detect optical output signals introduced from the output parts 41b of the core of the Planar Lightwave Circuit 40, and then check exactly the Planar Lightwave Circuit 40 and the input optical fiber block 30.
The reference numeral 60 is an output optical fiber block, and the reference numeral 70 is a powermeter. The output optical fiber block 60 accommodates plural optical fibers 21 which are corresponded with output parts 41b of the core in the Planar Lightwave Circuit 40. The powermeter 70 calculates the optical output signals introduced from the cores of the optical fibers 21 of the optical fiber block 60, and then checks the final status of the input optical fiber block 30, the Planar Lightwave Circuit 40 and the output optical fiber block 60.
The reference numerals 81 and 82 are micro-positioners, and reference numeral 83 is an upholder. The upholder 83 fixes the Planar Lightwave Circuit 40. The micro-positioners 81 and 82 fix the input and the output optical fiber blocks 30 and 60, respectively, and drive their locations at 6-axes directions, and position both sides of the Planar Lightwave Circuit 40 and each location and angle of the input and the output optical fiber blocks 30 and 60, respectively. The 6-axes, with reference to FIG. 1, are x, y and z axes at a side which is corresponded with each optical fiber block 30 and 60 and the Planar Lightwave Circuit 40, and xcex8x, xcex8y and xcex8z axes which are each angle of the x, y and z axes.
The reference numeral 80 is a microcomputer. The microcomputer 80 receives input signals introduced from the CCD camera 52, the infrared camera 51 and the power meter 70, and then controls each driving status of the micro-positioners 81 and 82.
With reference to FIGS. 2A and 2B, the operations of the above-described conventional structure will be explained as follows.
When one part of the core of the optical fiber 20 is connected to the laser source 10, and when another part of the core is accommodated in the input optical fiber block 30, they are both positioned in the input optical fiber block 30 and the Planar Lightwave Circuit 40 (S101). In this case, it is preferable that the optical fiber 20 accommodated in the input optical fiber block 30 and the input part 41a of the core 40 in the Planar Lightwave Circuit 40 must be positioned to accord with each other in a straight line. Substantially, since the core of the optical fiber 20 is very small, it is difficult for the optical fiber 20 and the input part 41a of the core 40 to be accorded with each other.
In such a status, an operator detects each positioned image of the input optical fiber block 30 and the Planar Lightwave Circuit 40 by using the microcomputer 80 and the CCD camera 52 (S102), and then decides whether the positions of the images are good. If the position of each image is not satisfactory (S103), the operator controls the initial position of the input fiber block 30 to another position for acquiring the determined optical output signal by means of the micro-positioner 81 (S104). The initial position of the input fiber block 30 represents a position for acquiring a determined optical output signal passing by the noise areas. It is accomplished generally by a blind-search such as an eye measurement by the operator, and by intuition according to his experiments, and the like. Accordingly, a great deal of time is wasted at the controlling step of this initial position of the total steps, and more time is wasted if the operator is a novice.
Next, the operator positions the lens 50 and the infrared camera 51 to the output part 41b of the core 41 of the Planar Lightwave Circuit 40 (S105), and detects an optical signal which is introduced from the Planar Lightwave Circuit 40, by means of the infrared camera 51 (S106). If the optical signal is not satisfied (S107), the operator detects exactly each position of the input optical fiber block 30 and the Planar Lightwave Circuit 40 (S108).
To explain the above-steps in detail, an explanation will follow. In a status that the input optical fiber block 30, the Planar Lightwave Circuit 40, the lens 50 and the infrared camera 51 are accorded almost in a straight line, the laser source 10 generates a light signal, and the light signal inside of the optical fiber 20 directs to the input optical fiber block 30. And then the light signal incident on the input part 41a of the core 41 in the Planar Lightwave Circuit 40 branches into plural paths through the core 41 so as to be introduced to a plurality of output parts 41b. The infrared camera 51 detects an optical signal introduced from the output parts 41b of the core 41 of the Planar Lightwave Circuit 40. The operator determines the positioning status between the input optical fiber block 30 and the Planar Lightwave Circuit 40 exactly by the signal until the signal has a good status continuously, S108.
Here, in supporting the input optical fiber block 30, the micro-positioner 81 drives the input optical fiber block 30 to 6-axes directions so as to position locations and angles of the corresponding side to the Planar Lightwave Circuit 40.
Next, in the state in which the input optical fiber block 30 and the Planar Lightwave Circuit 40 are positioned with each other, the operator moves a micro-positioner of output part 82 to the x-axis direction to position the Planar Lightwave Circuit 40 and the output optical fiber block 60 (S109). In this case, it is preferable that the core 41 accommodated in the output optical fiber block 60 and the output part 41b of the core 41 in the Planar Lightwave Circuit 40 are accorded in a straight line, respectively.
In such a status, the operator detects each positioned image of the output optical fiber block 60 and Planar Lightwave Circuit 40 by using the microcomputer 80 and the CCD camera 52 (S110), and decides whether the positioned images are good (S111). If each positioned image is not good, the operator controls an initial position of the output optical fiber block 60 to a position for acquiring a determined optical signal (S112). This series of operations is different only in detecting objects and their locations, in comparison with the controlling steps (S102-S104) of the initial position of the input optical fiber block 30, but their basic operations are the same. Accordingly, their detailed explanations are omitted.
The operator detects optical signals introduced from the core 41 to the input optical fiber block 60 by using a powermeter 70, S113, and decides whether the optical signals are good. If the optical signals are not good, S114, the operator detects exactly the final positioning status of the input optical fiber block 30, the Planar Lightwave Circuit 40 and the output optical fiber block 60, S115.
To explain the above-steps S113-S115, a detailed explanation follows.
In a status that the input optical fiber block 30, the Planar Lightwave Circuit 40 and the output optical fiber block 60 are positioned to acquire the initial output, the incident light into the input part 41a of the core 41 in the Planar Lightwave Circuit 40 through the input optical fiber block 30, is introduced into the plurality of the output part 41b of the core 41 in the Planar Lightwave Circuit 40, and is incident into the plural optical fiber 21 of the output optical fiber block 60.
This optical signal is directed into the inside of the optical fiber 21, and then it is directed to the powermeter 70 located at their back sides. The powermeter 70 calculates each intensity of the output optical signal introduced from the plural optical fiber 21, and applies the microcomputer 80. The microcomputer 80 then compares the output optical signals of the output optical fiber block 60 with the determined reference levels inputted in advance, and then detects the final status of the input optical fiber block 30, the Planar Lightwave Circuit 40 and the output optical fiber block 60, respectively.
If the optical signals detected by the powermeter 70 are not good, i.e., if the optical signals are under the predetermined reference levels, the positions of the Planar Lightwave Circuit 40 and the output optical fiber block 60 are controlled continuously until good optical signals are detected. Here, the micro positioner 82 drives the output optical fiber block 60 is 6-axes directions so as to position locations and angles of the corresponding side to the Planar Lightwave Circuit 40.
Next, if the optical signals detected by the powermeter 70 are good, the input optical fiber block 30, the Planar Lightwave Circuit 40 and the output optical fiber block 60 are adhered to each other by using adhesives. Accordingly, all positioning operations are finished (S116).
In such a conventional apparatus and its method for positioning optical fiber blocks and the Planar Lightwave Circuit, for the initial positions of the input and the output fiber blocks 30 and 60, that is, positions for acquiring the determined optical output signal passing by the noise areas, it is accomplished generally by a blind-search such as an eye measurement by the operator and by intuition according to his experiments, and the like. Accordingly, a great deal of time is wasted at the controlling steps of this initial position of the total steps, and more time is wasted if the operator is a novice.
Besides, since these positioning operations rely heavily on the expertise of the operator, and since it is difficult to acquire skilled technical employees, the positioning operations for mass production cannot be accomplished. Furthermore, since there are a lot differences, particularly in speed, between skilled hands and novices, there is a problem that overall productivity is lowered.
The present invention has been designed to overcome the above problems, and accordingly, it is a first object of the present invention to provide an apparatus and method for controlling the positioning of the optical fiber blocks and a Planar Lightwave Circuit, which positions quickly and correctly the optical fiber blocks and the Planar Lightwave Circuit with alignment marks, respectively.
A second object of the present invention is to provide an apparatus and method for controlling the positioning of the optical fiber blocks and a Planar Lightwave Circuit, which increases their quickness and repetition by controlling effectively the optical fiber blocks and the Planar Lightwave Circuit with alignment marks, respectively.
To achieve the above objects, the present invention provides an apparatus for positioning optical fiber blocks and a Planar Lightwave Circuit comprising: a micro-positioning means for fixing an input optical fiber block and an output optical fiber block with alignment marks, respectively, and for positioning the optical fiber blocks and a Planar Lightwave Circuit with alignment marks by means of controlling their positions; a position detecting means for detecting each position of the alignment marks of the input optical fiber block, the Planar Lightwave Circuit and the output optical fiber block: and a control means for judging each status of the alignment marks detected by the micro-positioning means, and then for controlling each operating status of the micro-positioning means.
Additionally, the apparatus comprises means for adhering, to contact the input optical fiber block, the Planar Lightwave Circuit and the output optical fiber block, respectively.
The position detecting means comprises: an upper camera for detecting the image of each alignment mark of the input optical fiber block, the Planar Lightwave Circuit and the output optical fiber block at the upper direction; and a side camera for detecting the image of each alignment mark of the input optical fiber block, the Planar Lightwave Circuit and the output optical fiber block at the side direction. It is preferable that the upper or side camera is a charge coupled device camera for converting detected light signals into electrical signals.
Preferably, the control means is capable of monitoring the image of each alignment mark detected by the position detecting means.
One, or both sides of the Planar Lightwave Circuit (PLC), and of the input and output optical fiber blocks are formed to give a slope.
The alignment marks are formed to have shapes in fabricating the PLCs, and the shapes are F-shaped marks. The alignment marks are for positioning the cores at the upper or the side parts of the Planar Lightwave Circuit.
To achieve the above objects, the present invention provides an optical fiber block with alignment marks comprising: a substrate having plural grooves formed on its upper part; optical fibers which are fixed in the grooves, and for directing optical signals; alignment marks formed on the upper part of the substrate, and for becoming a basis for positioning of the optical fibers; and an optical glass for covering disclosed upper sides of the substrate and the optical fibers.
The substrate additionally has adhesion stop grooves formed at both right and left sides of the plural grooves, which are V-shaped. The alignment marks are formed to have shapes in fabricating the PLCs, and the shapes are F-shaped marks. The alignment marks are to position the optical fibers at the upper or the side parts of an optical fiber block. The optical glass is made of a transparent material.
To achieve the above objects, the present invention provides a Planar Lightwave Circuit with alignment marks comprising: cores for branching one or more inputs into plural outputs, and for forming each waveguide; a clad for molding the cores; and alignment marks formed in the upper corners of the clad, and for becoming a basis for the positioning of a Planar Lightwave Circuit. The alignment marks are formed to have their shapes by the fabricating of the PLCs. The determined shapes are F-shaped marks. The alignment marks are for positioning the cores at the upper or the side parts of the Planar Lightwave Circuit
To achieve the above objects, the present invention provides an apparatus for positioning optical fiber blocks and a Planar Lightwave Circuit comprising: a micro-positioning means for fixing an input optical fiber block and an output optical fiber block with alignment marks, respectively, and for positioning the optical fiber blocks and a Planar Lightwave Circuit with alignment marks by means of controlling their positions; a position detecting means for detecting each position of the alignment marks of the input optical fiber block, the Planar Lightwave Circuit and the output optical fiber block; and a control means for judging each status of the alignment marks detected by the micro-positioning means, and then for controlling each operating status of the micro-positioning means.
The apparatus comprises additionally, means for adhering, to contact the input optical fiber block, the Planar Lightwave Circuit and the output optical fiber block, respectively.
The position detecting means comprises: an upper camera for detecting an image of each alignment mark of the input optical fiber block, the Planar Lightwave Circuit and the output optical fiber block at the upper direction; and a side camera for detecting the image of each alignment mark of the input optical fiber block, the Planar Lightwave Circuit and the output optical fiber block at the side direction. The upper or side camera is a charge coupled device camera for converting detected light signals into electrical signals. The control means is capable of monitoring the image of each alignment mark detected by the position detecting means. Both sides of the Planar Lightwave Circuit are formed to give a slope. One side of each optical fiber block is formed to give a slope. The alignment marks are formed to have shapes by fabricating the PLCs. The determined shapes are F-shaped marks. The alignment marks are for positioning the cores at the upper or the side parts of the Planar Lightwave Circuit.
To achieve the above objects, the present invention provides an apparatus for positioning optical fiber blocks and a Planar Lightwave Circuit comprising: a laser source for introducing optical signals into an input optical fiber block; micro-positioners for fixing input and output optical fiber blocks with alignment marks, respectively, and for positioning the optical fiber blocks and a Planar Lightwave Circuit with alignment marks by means of controlling their positions; position detectors for detecting each position of the alignment marks of the input optical fiber block, the Planar Lightwave Circuit and the output optical fiber block, respectively; a power meter for detecting optical output signals of the output optical fiber block; a controller for judging each status of the alignment marks detected by the micro-positioners, and then for controlling each operating status of the micro positioners; and an adhering part for contacting the input optical fiber block, the Planar Lightwave Circuit and the output optical fiber block, respectively.
The position detectors comprise: an upper camera for detecting the image of each alignment mark of the input optical fiber block, the Planar Lightwave Circuit and the output optical fiber block at the upper direction; and a side camera for detecting the image of each alignment mark of the input optical fiber block, the Planar Lightwave Circuit and the output optical fiber block at the side direction.
To achieve the above objects, the present invention provides a method for manufacturing an optical fiber block with alignment marks comprising: a first step of forming plural grooves on a substrate; a second step of forming alignment marks becoming a basis for positioning on the substrate; a third step of fixing optical fibers for directing optical signals in the grooves; and a fourth step of forming an optical glass on the substrate and the optical fiber disclosed.
The first step forms adhesion stop grooves at both ends on the substrate, and forms also plural V-shaped grooves between the adhesion stop grooves. The alignment marks in the second step are formed by fabrication to be F-shaped marks.
To achieve the above objects, in a method for manufacturing a Planar Lightwave Circuit with a core and a clad, a method for manufacturing a Planar Lightwave Circuit with alignment marks is characterized in forming alignment marks becoming a basis for positioning at the insides of the corners on the clad.
To achieve the above objects, the present invention provides a method for controlling an apparatus for positioning optical fiber blocks and a Planar Lightwave Circuit comprising: a first step for positioning an input optical fiber block, a Planar Lightwave Circuit and an output optical fiber block, respectively; a second step for controlling an initial position of the input optical fiber block, if the detected positions of each alignment mark of the input optical fiber block is not good; a third step for controlling an initial position of the output optical fiber block, if the detected positions of each alignment mark of the output optical fiber block is not good; a fourth step for controlling the exact positions of the optical fiber blocks according to the outcome when output optical signals detected from the output optical fiber block are compared with predetermined reference levels; and a fifth step for adhering the input optical fiber block, the Planar Lightwave Circuit and the output optical fiber block, respectively.
Accordingly, the apparatus and its controlling method for positioning optical fiber blocks and a Planar Lightwave Circuit according to the present invention can detect each of the alignment marks of the input optical fiber block, the Planar Lightwave Circuit and the output optical fiber blocks when optical fibers are branching, and then can position to quickly contact the initial positions of the input and output optical fiber blocks; that is, positions for acquiring determined optical output signals passing by the noise areas.